3516B and 3516C Engines For MT4400D AC Off-Highway Trucks Caterpillar

Use this procedure in order to troubleshoot an occurrence of a high exhaust temperature. Also, use this procedure if one of the following event codes is active.

Certain operating conditions may cause the calculated exhaust temperature to increase to a level that may damage engine components. If a high exhaust temperature occurs, the Electronic Control Module (ECM) derates the engine in order to reduce the calculated exhaust temperature. The engine is derated only to a level that allows the calculated exhaust temperature to return to an acceptable level.

Table 1

Event Codes
Code and Description	Conditions which Generate this Code	System Response
E278(1) High Exhaust Differential Temperature - least severe	The differential temperature for the exhaust is above the trip point temperature	The code is logged.
E278(2) High Exhaust Differential Temperature - moderate severity
E278(3) High Exhaust Differential Temperature - most severe
E321(1) High Right Exhaust Temperature - least severe	The manifold exhaust temperature has exceeded the trip point for the programmed delay time.	The code is logged.
E321(2) High Right Exhaust Temperature - moderate severity
E321(3) High Right Exhaust Temperature - most severe
E322(1) High Left Exhaust Temperature - least severe
E322(2) High Left Exhaust Temperature - moderate severity
E322(3) High Left Exhaust Temperature - most severe
1318-15 Engine Exhaust Temperature Bank Imbalance : High - least severe (1)	The differential temperature for the exhaust is above the trip point temperature	The code is logged.
1318-16 Engine Exhaust Temperature Bank Imbalance : High - moderate severity (2)
1318-0 Engine Exhaust Temperature Bank Imbalance : High - most severe (3)
2433-16 Engine Exhaust Gas Temperature - Right Manifold: High -moderate severity (2)	The manifold exhaust temperature has exceeded the trip point for the programmed delay time.	The code is logged. The alarm output is activated.
2433-0 Engine Exhaust Gas Temperature - Right Manifold: High - most severe (3)
2434-16 Engine Exhaust Gas Temperature - Left Manifold: High - moderate severity (2)
2434-0 Engine Exhaust Gas Temperature - Left Manifold: High - most severe (3)

Probable Causes

• Diagnostic codes

• Air inlet and exhaust system

• Engine operating conditions

• Fuel Injectors

• Obstructed aftercooler

• Separate Circuit Aftercooler (SCAC) temperature regulators

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Codes A. Establish communication between Caterpillar® Electronic Technician (Cat ET) and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Monitor the diagnostic codes on Cat ET. Determine if a code is active or logged. Note: Wait at least 30 seconds in order for diagnostic codes to become active.	Associated diagnostic codes	Result: A diagnostic code is active or logged. Repair: Troubleshoot any codes before continuing with this procedure. Verify that the repair eliminated the problem. Result: A diagnostic code is not active or logged. Proceed to Test Step 2.
2. Check the Air Inlet and Exhaust System for Problems A. Check for an air filter restriction. Clean plugged air filters or replace plugged air filters. B. Check the air inlet and exhaust system for restrictions and/or leaks. C. Check the performance of the turbocharger. Ensure that recommended maintenance is performed on the turbocharger.	Air inlet and exhaust system	Result: The air filter, air inlet system, exhaust system, and turbocharger are in good repair. Proceed to Test Step 3. Result: The air filter is restricted, air inlet and/or exhaust system is restricted or leaking, or a problem with the turbocharger is found. Repair: Repair or replace any necessary components. Verify that the repair eliminated the problem.
3. Check the Engine Operating Conditions A. Check the histogram to determine if the high exhaust temperature was due to normal operation. When possible, interview the operator. Determine if the engine is being operated under heavy load. Ensure that the engine is being operated at the proper engine speed. If derates are suspected, reset histogram and return the unit to service. If the histogram repopulates without fault codes, the engine was under normal operation.	Normal operation	Result: The code was logged during a heavy load. Repair: Reduce the load on the engine. Verify that the repair eliminated the problem. Result: The code was not logged during a heavy load. Proceed to Test Step 4.
4. Fuel Injectors Note: Faulty fuel injectors that deliver too much fuel will increase exhaust temperatures. A. Perform a "Cylinder Cutout Test" using Cat ET.	Fuel Injectors	Results: The injectors are OK. Proceed to Test Step 5. Results: The injectors are Not OK. Repair: Repair or replace the faulty fuel injectors. Verify that the repair eliminated the problem.
5. Check for an Obstructed Aftercooler A. The intake manifold air temperature can increase if the flow through the aftercooler is obstructed. Check the aftercooler for obstructions or debris. Ensure that the flow of air or coolant through the aftercooler is adequate.	Obstructed aftercooler	Result: The engine aftercooler was obstructed. Repair: Clear any obstructions. Verify that the repair eliminated the problem.
6. SCAC Temperature Regulators A. Check the operation of the SCAC temperature regulators. Refer to Specifications, "Water Temperature Regulator" for additional information.	Temperature Regulators	Result: The SCAC temperature regulators operate correctly. Result: There is a problem with the SCAC temperature regulators. Repair: Replace the regulators. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).